Venting valve to be used in venting bores of vulcanization molds

ABSTRACT

Vent valve for venting bores of vulcanization moulds, especially for the tread profile area, consisting of a valve sleeve, in which a valve insert and a wound spring are movably located, wherein the valve insert consists of a valve shank, which is at one end equipped with a disk and at the other end with a conical surface changing into backwards oriented conical end, and the movement of the valve insert is controlled by a delimiter of opening the valve. Inner surface of the valve sleeve is in its part located further away from disk provided with conical surface, oriented away from the disk, and the delimiter of opening the valve is formed by two mutually cooperating conical surfaces or parts of conical surfaces, wherein the conical surface formed at the end of the valve shank of the valve insert is oriented against the conical surface or part of conical surface of the valve sleeve.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.12/281,606, filed Sep. 3, 2008, now U.S. Pat. No. 7,645,131, issued Jan.12, 2010, which is a national stage entry of PCT Internationalapplication no. PCT/SK2007/050007 filed Feb. 26, 2007, which claimspriority to Slovakian application Serial No. PP 0044-2006 filed Mar. 3,2006, and which incorporates by reference the disclosure of eachapplication identified above.

TECHNICAL FIELD

The invention concerns a vent valve to be used in venting bores ofvulcanization molds for production of technical rubber products,especially for tire production. Vent valves according to the presentinvention are particularly suitable to be used in vulcanization moldsfor tire production for the tread area to prevent forming depressions orlateral flow projections.

BACKGROUND

Molds for tire vulcanization are equipped with venting bores, throughwhich air escapes, so that semi-finished tire placed in the mold bypressure acting from the side of mold cavity can acquire the shapecorresponding to the tool inserted in the vulcanization mold. Thisunvulcanized semi-finished product moves the air to the moldcircumference, where it escapes from the mold. At the same time the tirematerial enters the venting bores and projecting excess rubber results,which must be removed following the vulcanization.

Insufficient removal of air from the vulcanization mold causes faults onthe finished products, both depressions are formed in the tread area andthe material may be insufficiently heated and thus vulcanization of thesemi-finished product may be incomplete.

Vent valves and vulcanization forms equipped with vent valves are knownfrom EP 0774 333 (CZ 291837), where the vent valve for venting bore ofthe vulcanization mold contains a movable valve insert with a valveshank and a disk, wherein the valve insert may be pushed into the closedposition by pressure acting on that side of the disk, which is orientedto the cavity of the vulcanization mold, into which the vent valve isbuilt-in, and vice versa, the valve insert can be moved by means of aspring into an open position, if no pressure acting from the cavity onthe valve disk is present, wherein movement of the valve insert isdelimited by a stop, arranged at the end of the vent valve oriented awayfrom the cavity, for restricting the valve insert movement into the openposition to a path shorter than 2 mm, wherein, for the purpose of apossibility to dismount the valve insert, the stop is realized as a snapconnection provided with a clearance between the valve shank at one handand the valve body at the other hand. Delimitation of the vent valvepath is ensured by the snap lock. The snap lock is preferably located onthe valve shank or it is inserted into the valve body. A disadvantage ofthis solution is that the vent valve consists even of four components,namely of a valve body, a valve insert, a wound spring and a flexionspring, which represents the snap lock. Disassembly of some embodimentsof the vent valve according to the invention is also problematic.

The aim of the present invention is to create such vent valve, whichwill provide for reliable air venting of a vulcanization mold, willconsist of possibly the simplest parts, will be simply assembled anddisassembled and simultaneously, its price will be acceptable.

SUMMARY OF THE INVENTION

The above aim is achieved by a vent valve intended for venting bores ofvulcanization molds, especially for the tread area, consisting of avalve sleeve, in which a valve insert and a wound spring are movablylocated, wherein the valve insert is formed by a valve shank, which isequipped at one end with a disk and at the other end with a conicalsurface changing into backwards oriented conical end, and the valveinsert movement is delimited by a delimiter of opening the valve, thenature of which consists in that the inner surface of the valve sleeveis in its part further apart from the disk provided with conicalsurface, oriented away from the disk. Delimiter of the movement of thevalve insert (of opening the valve) is formed by two mutuallycooperating conical surfaces or parts of conical surfaces, wherein oneof the conical surfaces is the above mentioned inner surface of thevalve sleeve and the other conical surface is a conical surface createdat the end of the valve shank of the valve insert, which is orientedagainst the mentioned conical surface or part of conical surface of thevalve sleeve.

According to a preferred embodiment, the valve sleeve consists of apart, the outer diameter of which corresponds essentially to that of thebore of the vulcanization mold for embedding the valve, and of a parthaving a slightly smaller outer diameter. That part of the valve sleeve,the outer diameter of which corresponds essentially to that of the boreof the vulcanization mold for embedding the vent valve, is located moreclosely to the disk of the valve insert, while the disk of the valveinsert extends into the inner space of the vulcanization mold. Thesecond part of the valve sleeve, which has a smaller outer diameter thanthat of the bore for embedding the vent valve, is located further awayfrom the disk of the valve insert, thus more closely to the outer spaceof the vulcanization mold. This part of the valve sleeve having thesmaller diameter is provided with at least two longitudinal openings ornotch grooves.

The valve sleeve, as described above, may be formed as a singlerotational component or it may be formed by connecting, for example bypressing together, a separately produced rotational part as the parthaving the greater outer diameter, and a part having the smaller outerdiameter produced as a drawn piece.

Each of the longitudinal openings uniformly spaced along thecircumference of the part of the valve sleeve having smaller outerdiameter is provided with a springy shaped projection, oriented to theinner space of the sleeve, wherein each shaped projection contains apart of a conical surface on the inner wall of the valve sleeve forcooperation with the conical surface of the valve insert.

The valve insert, formed by a shank, which is provided at one end with adisk and at the other end with a conical surface changing into backwardsoriented conical end, may be produced as a single rotational componentor the valve insert disk may be produced separately and afterwardsdetachably attached to the valve insert shank.

The vent valve consists of three basic components, namely of a valvesleeve, a valve insert and a wound spring. The valve insert may bepushed into the closed position by pressure acting on the outer side ofthe disk, and the movement into the open position of the valve, when nopressure is acting in the direction from the inner of the vulcanizationmold, is ensured by the wound spring, acting on the lower side of thedisk. The displacement range (p) is given by the difference of thelengths (h, H) wherein the length of the valve sleeve is h and thelength of the valve insert is H.

The part of the valve sleeve, which is oriented to the cavity of thevulcanization mold, has greater outer diameter than the part of thevalve sleeve, which is located more closely to the outer side of thevulcanization mold, and the part of the valve sleeve having smallerdiameter is provided with longitudinal notch grooves or openingsprovided with shaped projections extending into the inner part of thesleeve. Openings or notch grooves in this part of the sleeve serve forbetter escape of air from the vulcanization mold and for creation of thenecessary elasticity of the valve sleeve, which is needed when mountingand dismounting the vent valve into and out of the mold.

The outer surface of the part of the valve sleeve with smaller diameter(the narrower part) is formed by a conical surface or rotational surfacehaving profile of a parabola curve.

Movements of the valve insert are delimited by a delimiter, arranged atthe end of the vent valve, wherein the delimiter restricts the movementof the valve insert into the open position. Delimiter of opening thevalve (displacement of the valve insert) is meant as abutment of twoconical surfaces or parts of conical surfaces facing each other, whereinone of them is a part of the inner surface of the valve sleeve and theother is a part of the valve insert.

Bending of the valve sleeve when mounting and dismounting the valveinsert is allowed by the notch grooves (at least 2) on the circumferenceof the valve sleeve mantle or deformation of the shaped projections (atleast 2), containing parts of conical surface, in the longitudinalopenings of the mantle, if this part has been produced as a drawn pieceaccording to another embodiment of the present invention.

After pressing such valves into the vulcanization mold, each of thevalves is pushed into the closed position by the rubber mixture of thetire semi-finished product when pressure is applied, and vice versa,each of the valves is pushed into its open position by means of a woundspring when the finished tire is removed.

For further improvement of cleanness and functionality of thecooperating elements, it is possible to furnish certain surfaces withanti-adhesive or anticorrosive layer.

As dismounting of venting valves from the mold is necessary only rarely,it is always sufficient to fix the valves in the segments of thevulcanization mold by pressing them in. For that purpose, diameter ofthe valve in dismounted state should always be slightly greater than theinner diameter of the respective venting bore.

An advantage of the vent valves according to the present invention isthat the valve insert can be, despite the delimiter of the openingmovement, easily dismantled by a force acting in the direction of thevalve insert axis into the cavity of the vulcanization mold, and thevalve can be easily assembled by acting of a force in the oppositedirection.

BRIEF SUMMARY OF THE DRAWINGS

The attached drawings show vent valves according to the presentinvention in various embodiments.

FIGS. 1.1, 1.2 and 1.3 show the vent valve according to Example 1, whereFIG. 1.1 shows a section through the vent valve, FIGS. 1.2 and 1.3 arethe outside views of the vent valve, wherein in FIG. 1.2 the brokenlines indicate the parts located inside the valve sleeve, which are notvisible from outside.

FIGS. 2.1 and 2.2 show the vent valve according to Example 2, where FIG.2.1 shows a section through the vent valve, FIG. 2.2 is the outside viewof the vent valve.

FIGS. 3.1 and 3.2 show the vent valve according to Example 3, where FIG.3.1 shows a section through the vent valve, FIG. 3.2 is the outside viewof the vent valve.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT EXAMPLE 1

The vent valve, shown in FIG. 1.1, consists of a valve sleeve (5), whichhas cylindrical shape and is provided with a cavity. The outer diameterof that part (5-1) of the valve sleeve (5), which, when used in theventing bore of a vulcanization mold, is located more closely to theinner space of the mold, is essentially the same as diameter of the borein the vulcanization mold for embedding the valve, and is greater thanthe outer diameter of the second part (5-4) of the sleeve (5), which isoriented outwards of the mold. This part (5-4) of the sleeve (5) havingsmaller outside diameter is provided with at least two longitudinallyoriented notch grooves (5-5) (FIG. 1.3), running from the sleeve end toits part (5-1) having greater outer diameter. These notch grooves allowair to escape from the vulcanization mold into the space created betweenthe cylindrical bore in the vulcanization mold and the tapered part(5-4) of the valve sleeve (5) and further away from the vulcanizationmold. This space is necessary when replacing the valve insert (4). Thevalve insert (4) is located in the cavity of the valve sleeve (5). Thevalve insert is a rotational component formed by a disk (4-1), shank(4-3) and conical surface (4-2). When pressure is acting from the cavityof the vulcanization mold, disk (4-2) abuts that edge of the valvesleeve (5), which oriented inwards the vulcanization mold. This edge ofthe valve sleeve (5) is equipped with conical surface (5-3). The valvesleeve (5) is at its inner surface in the lower part provided with astop surface (5-6) for the wound spring (6) and an inner conical surface(5-2), which together with the conical surface (4-2) of the valve insert(4) forms the delimiter for opening the valve.

On the shank (4-3) of the valve insert (4), there is located the woundspring (6), which ensures open position of the vent valve, if there isno pressure acting in the vulcanization mold. The wound spring (6) bearswith one end against the stop surface (5-6) and with the other endagainst the lower part of the disk (4-1). The lower part of the disk(4-1), abutting the conical surface (5-3) of the valve sleeve (5), isprovided with a corresponding conical surface. The valve insert (4) isprovided with a conical surface (4-2), changing into a backwardsoriented conical end, and the valve sleeve (5) is in the tapered part(5-4) provided with a facing inner conical surface (5-2), abutting theconical surface (4-2) of the valve insert (4), to prevent pushing thevalve insert (4) out of the valve insert (5) by the wound spring (6), sothat the delimiter of movement of the valve insert (4) is created. Theinner conical surface (5-2) of the sleeve (5) is interrupted only at thepositions of the longitudinal notch grooves (5-5).

The disk (4-1) of the valve insert (4) is provided with a conicalsurface, which, when pressure is acting on the disk (4-1) which is afterbuilding it in the vulcanization mold oriented into its inner space, canbe forced against the conical surface (5-3), created in thecorresponding part of the valve sleeve (5), thus closing the vent valve,and vice versa, if pressure in the inner part of the vulcanization moldacting on the disk (4-1) is released, the valve insert (4) is displacedby the wound spring (6) into the open position.

Movements of the valve insert are delimited by the valve delimiter,created by cooperation of the conical surface (4-2) of the valve insert(4), arranged at the end of the shank (4-3), which is further away fromthe inner space of the vulcanization mold, with the inner conicalsurface (5-2) of the valve sleeve (5).

Longitudinal notch grooves (5-5) allow in cooperation with the valveinsert (4), the wound spring (6) and the space in the bore of thevulcanization mold for air better to escape from the inner space of thevulcanization mold and they ensure elasticity and opening (releasing) ofthis tapered part (5-4) of the valve sleeve (5) to facilitate the valvedismantling when replacing the valve insert (4) and spring (6). Valveinsert (4), possibly with the wound spring (6), is removed from thevalve sleeve (5) by knocking it out inwards the vulcanization mold.

EXAMPLE 2

The vent valve, shown in FIG. 2.1, consists of a valve sleeve (5) ofcylindrical shape, which is provided with a cavity. The valve sleeve (5)is formed by tight connection, for example by pressing together twohollow cylindrical parts, namely a machined rotational body as part(5-1) having greater outer diameter, and a drawn piece (tapered part(5-4)) having at least in a part of it smaller outer diameter incomparison with the above part. Outer diameter of that part of the valvesleeve (5), which when used in the venting bore of the vulcanizationmold is located more closely to the inner space of the mold, isessentially the same as diameter of the bore for embedding the ventvalve of the vulcanization mold, so it has greater diameter than theouter diameter of the second part (5-4) of the valve sleeve (5), whichis located closer to the outer space. This part (5-4) of the valvesleeve (5) having smaller outer diameter is provided with twolongitudinal openings, while material of the sleeve wall extends intothe inner space of the valve sleeve (5) and creates a shaped projection(5-7). This shaped projection (5-7) contains at the inner side the innerpart of the conical surface (5-2) to cooperate with the conical surface(4-2) of the valve insert (4), thus creating the delimiter for openingthe vent valve. Longitudinal openings (shown in FIG. 2.2) allow air toescape from the vulcanization mold into the space created between thecylindrical bore of the vulcanization mold and the tapered part (5-4) ofthe valve sleeve (5) and further away from the vulcanization mold. Inthe cavity of the valve sleeve (5), there is located the valve insert(4). The valve insert is a rotational component formed by the disk(4-1), shank (4-3) and conical surface (4-2). When pressure is actingfrom the vulcanization mold cavity, disk (4-1) abuts that edge of thevalve sleeve (5), which is oriented inwards the vulcanization mold. Onthe shank (4-3) of the valve insert (4), there is located the woundspring (6), which ensures open position of the vent valve, if nopressure is acting inside the vulcanization mold. The wound spring (6)bears with one end against the stop surface (5-6) of the spring and withthe other end against the lower part of the disk (4-1).

The function of the vent valve according to the embodiment, shown inFIGS. 2.1 and 2.2, is the same as described in Example 1 for theembodiment according to FIGS. 1.1 to 1.3.

The tapered part (5-4) of the valve sleeve is provided with two oblongopenings, in which shaped projection (5-7) is created from the sleevewall material, which projection includes a part of conical surface(5-2). Movements of the valve insert are delimited by cooperation of theconical surface (4-2), arranged at the end of the shank (4-3), which isfurther away from the inner space of the vulcanization mold, with partsof the conical surfaces (5-2), created on the shaped projections (5-7),created in the longitudinal openings of part (5-4) of the valve sleeve(5).

Openings, provided with the shaped projection (5-7), in the tapered part(5-4) of the valve sleeve (5) allow in cooperation with the valve insert(4), the wound spring (6) and the space in the bore of the vulcanizationmold air better to escape from the inner space of the vulcanization moldand the shaped projection (5-7) ensures elasticity of this part of thevalve sleeve (5) to facilitate the valve dismantling when replacingvalve insert (4) and spring (6). The valve insert, possibly with thewound spring, can be removed from the valve sleeve (5) by knocking itout inwards the vulcanization mold.

EXAMPLE 3

FIG. 3.1 shows a further embodiment of the vent valve, which consists ofa valve sleeve (5) of cylindrical shape, which is provided with acavity. Outer diameter of that part (5-1) of the valve sleeve (5),which, when used in the venting bore of a vulcanization mold, is locatedmore closely to the inner space of the mold, is essentially the same asdiameter of the bore in the vulcanization mold for embedding the valve,and is greater than the outer diameter of the second part (5-4) of thesleeve (5), which is oriented outwards of the mold. This part (5-4) ofthe valve sleeve (5) having smaller outside diameter is provided with atleast two longitudinal notch grooves (5-5) (FIG. 3.2), running from thelower (outer) end of the sleeve (5) to its part (5-1) having greaterouter diameter. These notch grooves (5-5) allow air to escape from thevulcanization mold into the space created between the cylindrical borein the vulcanization mold and the tapered part (5-4) of the valve sleeve(5) and further away from the vulcanization mold. This space is alsonecessary when replacing the valve insert (4).

In the cavity of the valve sleeve (5), there is located the valve insert(4). The valve insert is a rotational component, which is in thisembodiment formed by the disk (4-1) as a separately produced part,attached to the upper part of the shank (4-3) and conical surface (4-2),which changes to backwards oriented conical end. When pressure is actingfrom the vulcanization mold cavity, disk (4-1) abuts that edge of thevalve sleeve (5), which is oriented inwards the vulcanization mold. Thisedge of the valve sleeve (5) is equipped with inner conical surface(5-3). The valve sleeve (5) is at its inner surface in the lower partprovided with a stop surface (5-6) for the wound spring (6), and aninner conical surface (5-2), which together with the conical surface(4-2) of the valve insert (4) forms the delimiter for opening the valve.

The function of the vent valve according to this embodiment is the sameas already described function of the valve according to Example 1, withthe difference that when opening or closing the valve, only disk (4-1)is moving, which is made as a separate part of the valve insert (4). Inthe open position, there is space created between the lower part of thedisk and the end of the shank (4-3), wherein the height of this spacecorresponds to the amount of displacement p, i.e. to the valve travel.During the action of the valve, the shank (4-3) of the valve insertstays in this case at rest.

I hereby claim the following:
 1. A vent valve for use with tire molds,comprising: a valve sleeve having a first portion and a second portionand having an aperture extending there through between a first end and asecond end of the valve sleeve, the first portion of the valve sleevebeing insertable into a bore of a tire mold and the second portionincluding one or more openings extending there through with a shapedprojection extending into the aperture from each of the openings; avalve insert located within the aperture of the valve sleeve, the valveinsert including a valve shank that is at one end equipped with a diskand near the other end with a surface extending at least partiallyradially outward relative to valve shank; and, a wound spring locatedwithin the valve sleeve about the valve insert; wherein, the vent valvefurther comprises a delimiter for limiting movement of the valve insertrelative to the valve sleeve, the delimiter being formed by the surfacenear the other end of the valve shank and a surface of the shapedprojection.
 2. The vent valve of claim 1, wherein the valve sleeve firstportion has an outer diameter that is larger than an outer diameter ofthe valve sleeve second portion.
 3. The vent valve of claim 2, whereinthe valve sleeve first portion is snugly inserted into a vent bore of atire mold.
 4. The vent valve of claim 1, wherein the wound springnormally biases the valve insert into an open position.
 5. The ventvalve of claim 1, wherein the valve sleeve second portion openingsprovide an exhaust point for pressurized air travelling through the ventvalve.
 6. The vent valve of claim 1, wherein the first end of the valvesleeve further comprises a conical surface that is complementary to aconical surface of the disk.
 7. The vent valve of claim 5, wherein theshaped projections are sufficiently deformable to enable the valve shankto be removed from the valve sleeve.
 8. The vent valve of claim 1,wherein the valve shank disk is removably attached to the remainder ofthe valve shank.
 9. The vent valve of claim 1, wherein the outwardlyextending surface at the other end of the valve shank is an at leastpartially conical surface, and the surface of the shaped projectionforming the delimiter with the valve shank surface is also an at leastpartially conical surface.
 10. A vent valve for use with tire molds,comprising: a valve sleeve having a first portion and a second portionand having an aperture extending therethrough between a first end and asecond end of the valve sleeve, the first portion of the valve sleevebeing insertable into a bore of a tire mold and the second portionincluding one or more openings extending through a thickness of thesleeve, the openings having a length extending from the second end ofthe valve sleeve in a generally longitudinal direction of the sleevetoward the first portion; a valve insert located within the aperture ofthe valve sleeve, the valve insert including a valve shank that is atone end equipped with a disk and near the other end with a surfaceextending at least partially radially outward relative to the valveshank; and, a wound spring located within the valve sleeve about thevalve insert; wherein, the vent valve further comprises a delimiter forlimiting movement of the valve insert relative to the valve sleeve, thedelimiter being formed by the outwardly extending surface near the otherend of the valve shank and a surface of the valve sleeve.
 11. The ventvalve of claim 10, wherein the valve sleeve first portion has an outerdiameter that is larger than an outer diameter of the valve sleevesecond portion.
 12. The vent valve of claim 10, wherein the wound springnormally biases the valve insert into an open position.
 13. The ventvalve of claim 10, wherein the valve sleeve second portion openings forman exhaust point for pressurized air travelling through the vent valve.14. The vent valve of claim 10, wherein the first end of the valvesleeve further comprises a conical surface that is complementary to aconical surface of the disk.
 15. The vent valve of claim 10, wherein theopenings provide sufficient flexibility in the second portion to enablethe valve shank to selectively be removed from the valve sleeve.
 16. Thevent valve of claim 10, wherein the outwardly extending surface at theother end of the valve shank is an at least partially conical surface,and the surface of the valve sleeve forming the delimiter with the valveshank surface is also an at least partially conical surface.
 17. Thevent valve of claim 10, wherein the valve shank disk is removablyattached to the remainder of the valve shank.